The vitreous separates two different tissues of the eye - the lens and retina - by providing a transparent system that is permeable to small molecules but impermeable to cells, and also provides mechanical protection for the zonules and retina, which are sensitive to mechanical dislocation. Both hyaluronic acid (HA) and collagen are believed to be important in the physiology of the vitreous, however there is no information concerning how the level of HA in the vitreous is regulated, nor is there definitive evidence on the cellular origin of vitreous collagen. The proposed research represents continuation of studies designed to provide information on the biosynthesis and regulation of HA in the vitreous. The role of hormones and ascorbic acid on the biosynthesis of hyaluronic acid by hyalocytes in culture will be studied. The interaction between hyaluronic acid and collagen plays a key role in vitreous function, therefore we will extend our studies to include the determination of collagen production by hyalocytes and how this is affected by the concentration and molecular size of HA. The role of ascorbic acid in the biosynthetic pathway of collagen production by hyalocytes will also be determined. As the vitreous contains the highest levels of ascorbate of all extracellular matrices, an understanding of the role of this vitamin in the production of both HA and collagen will provide further information concerning the interrelationships basic to the maintenance of vitreous homeostasis.